import os
from PyPDF2 import PdfReader, PdfWriter
import tkinter as tk
import time
from tkinter import filedialog as fd
from PyPDF2 import PdfFileReader, PdfFileWriter
import tkinter.messagebox


def GetFileName(dir_path):
    file_list = [os.path.join(dirpath, filesname)
                 for dirpath, dirs, files in os.walk(dir_path)\
                 for filesname in files]
    return file_list


def MergePDF(dir_path, file_name):
    output = PdfWriter()
    outputPages = 0
    file_list = GetFileName(dir_path)
    for pdf_file in file_list:
        print("文件：%s" % pdf_file.split('\\')[-1], end=' ')
        # 读取PDF文件
        input = PdfReader(open(pdf_file, "rb"))
        # 获得源PDF文件中页面总数
        pageCount =  len(input.pages)
        outputPages += pageCount
        print("页数：%d" % pageCount)
        # 分别将page添加到输出output中
        for iPage in range(pageCount):
            output.add_page(input.pages[iPage])
    print("\n合并后的总页数:%d" % outputPages)
    # 写入到目标PDF文件
    print("PDF文件正在合并，请稍等......")
    with open(os.path.join(dir_path, file_name), "wb") as outputfile:
        # 注意这里的写法和正常的上下文文件写入是相反的
        output.write(outputfile)
    tkinter.messagebox.showinfo('合并成功',"\n合并后的总页数:"+f'{outputPages}')
    print("PDF文件合并完成")


# 选择待分割文件
def select_out():
    # path_save = fd.asksaveasfilename(defaultextension='*.pdf', filetypes=file_types)
    path_save = fd.askdirectory()
    print(path_save)
    # a = fd.askdirectory()
    if path_save != '':
        button_split['state'] = 'normal'
        pdf_in.set(path_save)


def pdf_split():
    printout = pdf_out.get() + '.pdf'
    printin = pdf_in.get().replace('/',"\\")+""
    MergePDF(printin, printout)


global pdf_in, pdf_out, button_input, button_split


def main(root3):
    global pdf_in, pdf_out, button_input, button_split
    pdf_in = tk.StringVar()
    pdf_out = tk.StringVar()

    label_input = tk.Label(root3, text='①选择要合并pdf文件夹：')
    entry_input = tk.Entry(root3, textvariable=pdf_in, width=45)
    button_input = tk.Button(root3, text='①选择文件夹', command=select_out)
    # button_input['state'] = 'disabled'

    page_out = tk.Label(root3, text='②合并pdf文件名：')
    page_out_ = tk.Label(root3, text='（命名格式为‘XXX’)')
    entry_out2 = tk.Entry(root3, textvariable=pdf_out, width=45)

    button_split = tk.Button(root3, text='③执行合并', command=pdf_split, width=20, height=3)
    button_split['state'] = 'disabled'

    label_input.place(x=10, y=10)
    entry_input.place(x=10, y=35)
    button_input.place(x=350, y=32)

    page_out.place(x=10, y=80)
    page_out_.place(x=10, y=105)
    entry_out2.place(x=10, y=125)

    button_split.place(x=220, y=240)


root2 = tk.Tk()
# 窗口尺寸
# root.geometry('400x300')
# 窗口居中
sw = root2.winfo_screenwidth()
sh = root2.winfo_screenheight()
c = (sw - 400) / 2
d = (sh - 300) / 2
# print(a,b,c,d)
root2.geometry('605x500+%d+%d' % (c, d))
# 软件标题
root2.title('PDF合并软件')
# 软件左上角图标
# root2.iconbitmap('tubiao.ico')
# 窗口大小不可调
root2.resizable(width=False, height=False)

root = tk.Frame(root2, width=605, height=500)
root.place(x=0, y=0)
main(root)

root2.mainloop()

time.sleep(10)

# if __name__ == '__main__':
#     # 设置存放多个pdf文件的文件夹
#     dir_path = r'E:\Python\合并pdf'
#     # 目标文件的名字
#     file_name = "合并版.pdf"
#     MergePDF(dir_path, file_name)

可设置合并后保存文件夹

import os
from PyPDF2 import PdfReader, PdfWriter
import tkinter as tk
import time
from tkinter import filedialog as fd
from PyPDF2 import PdfFileReader, PdfFileWriter
import tkinter.messagebox


def GetFileName(dir_path):
    file_list = [os.path.join(dirpath, filesname)
                 for dirpath, dirs, files in os.walk(dir_path)\
                 for filesname in files]
    return file_list


def MergePDF(dir_path, file_name,pdfinputout):
    output = PdfWriter()
    outputPages = 0
    file_list = GetFileName(dir_path)
    for pdf_file in file_list:
        print("文件：%s" % pdf_file.split('\\')[-1], end=' ')
        # 读取PDF文件
        input = PdfReader(open(pdf_file, "rb"))
        # 获得源PDF文件中页面总数
        pageCount = len(input.pages)
        outputPages += pageCount
        print("页数：%d" % pageCount)
        # 分别将page添加到输出output中
        for iPage in range(pageCount):
            output.add_page(input.pages[iPage])
    print("\n合并后的总页数:%d" % outputPages)
    # 写入到目标PDF文件
    print("PDF文件正在合并，请稍等......")
    with open(os.path.join(pdfinputout if pdfinputout  else dir_path, file_name), "wb") as outputfile:
        # 注意这里的写法和正常的上下文文件写入是相反的
        output.write(outputfile)
    tkinter.messagebox.showinfo('合并成功',"\n合并后的总页数:"+f'{outputPages}')
    print("PDF文件合并完成")


# 选择待分割文件
def select_out():
    # path_save = fd.asksaveasfilename(defaultextension='*.pdf', filetypes=file_types)
    path_save = fd.askdirectory()
    print(path_save)
    # a = fd.askdirectory()
    if path_save != '':
        button_split['state'] = 'normal'
        button_input_out['state'] = 'normal'
        pdf_in.set(path_save)

# 选择待分割文件
def select_save():
    # path_save = fd.asksaveasfilename(defaultextension='*.pdf', filetypes=file_types)
    path_save = fd.askdirectory()
    print(path_save)
    # a = fd.askdirectory()
    if path_save != '':
        button_split['state'] = 'normal'
        pdf_input_out.set(path_save)


def pdf_split():
    printout = pdf_out.get() + '.pdf'
    printin = pdf_in.get().replace('/',"\\")+""
    pdfinputout= pdf_input_out.get().replace('/',"\\")+""
    MergePDF(printin, printout,pdfinputout)


global pdf_in, pdf_out, button_input, button_split, pdf_input_out, button_input_out


def main(root3):
    global pdf_in, pdf_out, button_input, button_split, pdf_input_out, button_input_out
    pdf_in = tk.StringVar()
    pdf_out = tk.StringVar()
    pdf_input_out = tk.StringVar()

    label_input = tk.Label(root3, text='①选择要合并pdf文件夹：')
    entry_input = tk.Entry(root3, textvariable=pdf_in, width=45)
    button_input = tk.Button(root3, text='①选择文件夹', command=select_out)
    # button_input['state'] = 'disabled'

    page_out = tk.Label(root3, text='②合并pdf文件名：')
    page_out_ = tk.Label(root3, text='（命名格式为‘XXX’)')
    entry_out2 = tk.Entry(root3, textvariable=pdf_out, width=45)

    label_input_out = tk.Label(root3, text='③选择要保存pdf文件夹：')
    page_out_out = tk.Label(root3, text='（若不选择保存文件夹，默认保存到合并文件夹’)')
    entry_input_out = tk.Entry(root3, textvariable=pdf_input_out, width=45)
    button_input_out = tk.Button(root3, text='③选择文件夹', command=select_save)
    button_input_out['state'] = 'disabled'

    button_split = tk.Button(root3, text='④执行合并', command=pdf_split, width=20, height=3)
    button_split['state'] = 'disabled'

    label_input.place(x=10, y=10)
    entry_input.place(x=10, y=35)
    button_input.place(x=350, y=32)

    page_out.place(x=10, y=80)
    page_out_.place(x=10, y=105)
    entry_out2.place(x=10, y=125)

    label_input_out.place(x=10, y=175)
    page_out_out.place(x=10, y=195)
    entry_input_out.place(x=10, y=220)
    button_input_out.place(x=350, y=215)

    button_split.place(x=220, y=280)


root2 = tk.Tk()
# 窗口尺寸
# root.geometry('400x300')
# 窗口居中
sw = root2.winfo_screenwidth()
sh = root2.winfo_screenheight()
c = (sw - 400) / 2
d = (sh - 300) / 2
# print(a,b,c,d)
root2.geometry('605x500+%d+%d' % (c, d))
# 软件标题
root2.title('PDF合并软件')
# 软件左上角图标
# root2.iconbitmap('tubiao.ico')
# 窗口大小不可调
root2.resizable(width=False, height=False)

root = tk.Frame(root2, width=605, height=500)
root.place(x=0, y=0)
main(root)

root2.mainloop()

time.sleep(10)

# if __name__ == '__main__':
#     # 设置存放多个pdf文件的文件夹
#     dir_path = r'E:\Python\合并pdf'
#     # 目标文件的名字
#     file_name = "合并版.pdf"
#     MergePDF(dir_path, file_name)